Q: Lion:WiFi not autoconnecting after sleep mode

How do you get write permission to modify that file?  When TextEdit opens the file it says "locked" in the header after the file name.  I tried changing the permissions of the .plist file using get info> and changing permission from read only to read and write but that did not work.  The file still says locked. 

Deleting the com.apple.airport.preferences.plist file worked for me

The steps worked for me.

1.Renew DHCP lease from System Preferences>Network>Advanced>TCP/IP

2.Set Service order with Wi-Fi on top.

3.Remove all prefered networks including the home network from prefered networks from System Preferences>Network>Advanced>Wi-Fi

4.Remove all the saved wifi passwords from keychain access(Utilities>Keychain Access). Wi-Fi passwords are denoted as Airport Network Passwords under kind. (Note : Do this step,only if you remember your network key provided by your ISP)

5.Remove System Configuration folder to the desktop from Macintosh HD>Library>Preferences>

Hope these steps work out for you as well.

Thanks

Still having issues after all the suggestions. This has to be a bug!

I tried both Avrahqedivra and swarupfromindia's suggestions and neither worked for me.

The autologin key did it for me, although the network I want to connect to has to be the first one in the list of Preferred Networks.

Thanks for the tip .

Same/similiar problems...... Early 2011 MBP

None of the above worked for me...

I have a Airport Extreme at home dual band.  One before the current slightly "better" transmission one.

Just to keep trying different things i brought it to work and its been connected now for over a hour no problems.

Works wireless is just a belkin isp provider viop clone nothing special.

Have been connected now for over 3 hours no problems....

I wonder if its anything to do with a incompatability with the extremes 5ghz....??

Anyhoo hopefully someone can figure it out....

Many phone calls to apple and still no where.  Last i left off with them was i will take it into their genius centre..... but the hassles of all that.... argh!

Just spoke with an Apple Engeneer. They know that the problem exists and are researching to find the cause. They said that, so far, nothing can be done to fix it. A system update should fix it in the near future.

I hope so!

Even though autoConnect is set to true in my preferences, I ocassionally have the problem of connecting to my home network and other networks after the computer comes back from sleep. 

Sometimes I have the feeling that the routine that looks for available networks either does not start, or stops looking just before the preferred network broadcasts its presence.

I never had a comparable problem with my iPad in the same networks I have problems with my MacBook Air. I wonder what the difference between the iPad and the MacBook is.

update:

my wifi card now is totally not working....!

"no hardware installed"

man alive what a great month im having - just got Lion installed on mid 2009 now dead completely and now the probs with the early 2011 cmon Apple!

wow! this really worked for me. thanks my friend from Paris!

Hei

This did the trick for me too.

Thankyou

The new lion update (10.7.3) seems to have resolved my problem.  The release notes mention a fix for this. 

http://support.apple.com/kb/HT5048

6th bullet point: "Resolve a Wi-Fi connection issue when waking from sleep"

Matrix,

Did you ever install a SL driver on the Lion machine at some point ? I have had that break my WiFI on a 10.7.3 upgrade. Can you paste your kernel.log here after a reboot ( from around the time the machine reboots)

10.7.3 upgrade doesn't improve mine. It is still suffering wifi dropping off after waking up from sleep.